As a result of the method of manufacturing hard gelatine capsules, the inner wall of these capsules is coated with lubricant and/or mould release agents. This leads to an increased adhesion of powder to the inner walls, which cannot be delivered to the patient in the case of capsules for inhalation. In addition, the parameters of “mass delivered” and “inhalable proportion” are subject to a wide range of fluctuations.
It is known from the prior art that special capsules, e.g., CONI-SNAP® two-piece gelatin capsules (Capsugel), which have a reduced coating of lubricant or mould release agent, can be used for inhalation purposes. This coating can be removed using solvents. However, cleaning with solvents is extremely expensive on an industrial scale and is therefore only suitable under certain conditions. In addition, the residual solvent content has to be checked thereafter.
The aim of the present invention is to provide a simple method of cleaning the inner wall of hard gelatine capsules for use in inhalation therapy.